Forest deadwood helps provide some 6,000 species of plants and animals with habitat or food.

(Jan Geerk / schweizfotos.com)

Mountain forest in autumn in eastern Switzerland.

(Michael Sengers/ Switzerland fotos.com)

Forest reserves take up 5% of Swiss forestland, offering a retreat to numerous animals.

(Gaethan Bally / Keystone)

A forested brook in canton Bern.

(Jan Geerk / Switzerland fotos.com)

Forest biodiversity is huge: as many as 25,000 species of plants and animals depend on Swiss forestland.

(Picture: Jerzy Opioła)

The wren, one of many species found in Swiss forests, prefers areas with deadwood.

(Stephan Rieben, SVS / BirdLife Switzerland)

A part of the Gantrisch Nature Park in canton Bern shows the forest growing back from a major storm in 1999.

(Terence du Fresne / swiss-image.ch)

With climate change, forests increasingly contend with pests such as this bark beetle housed inside a spruce bark.

(Gabriele Putzu / Keystone)

A woodsman with the help of his horse hauls tree trunks from a hill in canton Lucerne. The horses are gentler on the forests than large timber harvesters.

(Sigi Tischler / Keystone)

Cowslip in a forest in canton Schwyz.

(Gaetan Bally / Keystone)

A runner near Zurich takes to a forest, one of the many recreational pursuits it offers.

(Andreas Gonseth / Keystone)

Dozens of species of trees can be found in Swiss forests, where spruce, fir and beech are by far the most prevalent.

(Michael Sengers/ schweizfotos.com)

A lone mushroom near the forest above Alpthal in canton Schwyz.

(Photo: Urs Keller / Ex-Press)

A fungus from Asia afflicts a tree.

(Forest conservation Switzerland / WSL)

A forest worker in Spreitenbach.

(Photo: Heike Grasser / Ex-Press)

Tree trunks collected in the forest area Cavagnago in Faido, after heavy snow caused extensive damage.

(Gabriele Putzu / Keystone / Ti-Press)

Wooden bridge at Kemmeriboden-Tschannen, a product of Swiss forestland.

(Image: WVS)

Mar 21, 2016 - 10:00

It is easy to lose sight of the forest for the trees – to take for granted the myriad ways in which forests and trees are vital to the world’s health.

For this year’s celebration of world forests, the United Nations emphasizes that forests are key to supplies of fresh water, the basic building block of all life. Three-quarters of the world’s accessible fresh water comes from forested watersheds and wetlands.

A third of the world’s largest cities get a major part of their drinking water from protected forest areas. One of every five people on the planet depends on forests for their livelihood, according to the UN. Forests shelter 80% of the animals, plants and insects that live on land.

About a third of Switzerland – and a third of the Earth – is forested. The total area in Switzerland is increasing, particularly in the Alps. Each year, with a rising world population that is now up to 7.125 billion, the world loses 13 million hectares of forestland, which is converted to agriculture and other uses.

An area nearly equal in size to South Africa – 129 million hectares of forestland – was lost in the quarter century since 1990, the UN reported last year. The deforestation accounts for 12 to 20% of the global heat-trapping gases that contribute to climate change.

Forests now cover 30.6% of the world’s land areas, or 3.999 billion hectares, down from 31.6%, or 4.128 billion hectares, in 1990. More forest areas are gaining protection, however, as nations get better at forest management.